Tried using a heat gun to free a seized caliper bolt and it cracked the bracket

Had a 2012 Civic in the bay with a rear caliper that wouldn't budge. The bolt was rusted solid, so I figured I'd give my new heat gun a shot instead of the torch, thinking it would be safer. I heated the bracket area for a good five minutes, got it nice and hot, and went in with the breaker bar. The bolt snapped off clean, but then I saw a hairline crack running from the bolt hole down the bracket. The whole thing was junk. Learned that focused heat on a cast piece like that, even from a gun, can make it brittle if you're not super careful about where you aim. Now I'm out a caliper bracket and the job just got way bigger. Anyone have a better method for these that doesn't risk cracking the housing?

3 comments

3 Comments

patel.daniel2mo ago

That's a tough break, man. Cast parts really don't like sudden, focused heat. In my experience, a good penetrating oil and some patience works better for those. Soak it for a day if you can, then use an impact with short bursts, not a steady pull on a breaker bar. Sometimes tapping the bolt head with a hammer while you turn it can shock it loose. Your mileage may vary, but I've had less trouble that way.

luna_green1mo ago

Oh man, reminds me of the time I tried to unscrew a stuck garden hose and ended up flooding my whole driveway.

the_sam2mo ago

Nah, heat works fast if you're careful, @patel.daniel.